Screen printing machine employing a reciprocating printing and feed plate

ABSTRACT

A screen printing machine has a reciprocating printing and feed plate and retractable stops combined and cooperating with said plate so that the material to be printed moves forward over the plate in a stepwise manner. The screen is mounted over this plate and reciprocates with it so that the material passes under the screen. While it is under the screen a relatively stationary printing squeegee is lowered into its operative position and printing is thereby effected.

Uni-ted States Patent Inventor Heinrich Ronge 115 Bergerhide,Wuppertal-E, Germany Appl. No. 880,791 Filed Nov. 28, 1969 Patented May11, 1971 Priority Apr. 27, 1967 Germany Continuation-impart ofapplication Ser. No. 723,678, Apr. 24, 1968, now abandoned.

SCREEN PRINTING MACHINE EMPLOYING A RECIPROCATING PRINTING AND FEEDPLATE 10 Claims, 26 Drawing Figs.

U.S. Cl 101/124 Int. Cl B4ll 27/06 FieldofSearch l0l/l24, 126, 14, 129

[56] References Cited UNITEDSTATESPATENTS 2,498,9l7 2/1950 GZHUSO101/124 2,917,997 12/1959 Bl3Ck..... lOl/l26 3,078,792 2/1963 10315186..101/126 3,109,365 11/1963 Karlyn.... 101/124 3,199,449 8/1965 Jaffetal.101/129 3,252,411 5/1966 Black 101/124 Primary Examiner-William B. PennAssistant ExaminerE. M, Coven AttameyMichael S. Striker ABSTRACT: Ascreen printing machine has a reciprocating printing and feed plate andretractable stops combined and cooperating with said plate so that thematerial to be printed moves forward over the plate in a stepwisemanner. The screen is mounted over this plate and reciprocates with itso that the material passes under the screen. While it is under thescreen a relatively stationary printing squeegee is lowered into itsoperative position and printing is thereby effected.

A? rm i lSl Patented May 11, 1971 I 3,577,914

7 Sheets-Sheet 4 FIG. 72

INVENTOR IIE/ um (2mm:

Patented May 11, 1971 1 3,577,914

7 Sheets-Sheet 5' FIG. 73

mvzmon "6 11/1101 Qru I:

ATTORNEY Patented May 11, 1911 7 Sheets-Sheet 6 Patented May 11, 1971 '7Sheets-Sheet 7 I 37 5 FIG 2.0

LL l 1 T l I INVENTOR i v I I Heuvu/m gzwa'a' 0 -01mm j ATTORNEY SCREENPRINTING MACHINE EMPLOYING A RECIPROCATING PRINTING AND FEED PLATE CROSSREFERENCE TO RELATED APPLICATION This is a continuation-in-part of myearlier application, Ser. No. 723,678,'now abandoned,filed on Apr. 24,19 68 and entitled Screen Printing Machine.

BACKGROUND OF THE INVENTION This invention relates to screen printing.

It is the nature of the screen printing process, as for no otherprinting process, that it can be used for a particularly wide range ofdifferent materials. The types of machine employed therefore makeallowances for this fact.

However, these known machines have various drawbacks. in certain casesonly a small hourly output can. be obtained since the individualoperations have to take place in succession. in others, in which thematerial being printed is taken off by grippers which secure it, thethree processes of feeding (laying on), printing and removal (takingoff) may be carried out simultaneously, which is an advantage. However,the disadvantage of this type if the absolute necessity of a grippermargin on the material being printed on, a disadvantage which isparticularly serious if valuable material is being processed; apart fromthis an additional'operation has to be carried out to cut off thegripper margin and this is particularly inefficient-if the material hasto be cut separately and not as part of the cycle. The latter type ofmachines cannot print on specially thick material (as it cannot begrasped by the gripper) or irregular molded shapes with parallelsurfaces.

SUMMARY OF THE INVENTION It is an object of the invention to provide ascreen printing machine which is free from the aforementioneddisadvantages.

A further object of theinvention is to provide such a machine which canbe used for printing on a wide variety of materials, has a high outputand requires no gripper margin on the material to be printed.

ln pursuance of these objects, and others which will become apparenthereafter, a machine according to one embodiment of my inventioncomprises, briefly stated, elongated baseplate means having an uppersurface and being reciprocable longitudinally in predetermineddirections and in working strokes of predetermined length, so thatmaterial to be printed and which is located on the surface tends toshare such strokes, screen means mounted above the baseplate means formovement toward and away from an upper surface of the same, clampingmeans associated with the screen means for intermittently clamping thelatter against the baseplate means, mounting means mounting the screenmeans and the clamping means on the baseplate means for reciprocationwith the same, and blocking means operatively associated with thebaseplate means for blocking material on the surface at the end of therespective working stroke from sharing with the baseplate means thesubsequent return stroke, whereby the material advances stepwise overthe upper surface in one of the predetermined directions.

reference to the direction of reciprocation and is controlled,

over the screen and thereby. effect the printing. After'the printingprocess the material is removed on the same advanc- The clamping meansmay be mounted, e.g., in supporting make the material pass beyond theblocking means which may" be in form of a bridge which is stationarywith respect to the direction of reciprocation. When the material haspassed through, the bridge is lowered and acts as a barrier for thematerial, when the baseplate carries out the return stroke. ln

this way the material can be conveyed forward through two or morestations. When it is below the screen which is fixed in the clampingmeans, and the baseplate moves forward, the material is printed by astationary squeegee which is stationary with ing principle.

Printing material of any thickness can obviously be treated in this way,provided that the clamping means for the screen, the bridges and thesqueegee are made suitably adjustable in height. Instead of thestationary bridges, pins which can be raised and lowered, may be used,if the combined printing base contains longitudinal slots through whichthe pins may project or withdraw. The pins must then be controlled bysuitable-means so that on the forward movement of the com-' binedbaseplate they are retracted beneath the surface thereof, whereas on thebackward movement they project above the surface of the baseplate andthus prevent the printing material from moving back with the plate.-

Instead of bridges or pins, it is possibleto operate with lateralblocking arms, which are then always drawn apart to left and right farenough from the center to let the printing material'lying on thebaseplate pass on the forward stroke, and

maintained at the various stations. Instead of vacuum,

mechanical securing means or magnets mounted'on'the baseplate may beemployed where the nature of the printing.

material so permits.

The bridges, lateral arms and pins described above are provided to holdback the printing material when the baseplate carries out the returnstroke, and the advantage of the inven-- tion resides chiefly in thefact that by their use a wide variety of materials can be advanced andprinted; For. example,- plastic parts, plastic folders, ash trays, sawblades, tiles,

rectangular bottles and many other materials maybe advanced and printedwith the same ease as sheets. Even parts without any parallel surfacesmay be printed, provided that a guide of e.g. prismatic cross section ismounted on the baseplate.

It is also possible to equip the printingstation so that-a pickupimplement receives the material. If thin plastic lids are taken as' anexample of the material, thesemay be received at the printing station bya plunger which may be controlled so that it acts as'a support whenraised for the printing process and is lowered into general plane of thebaseplate when the.

printing material is moved on.

In known specialized 'machines operating on the. lineproductionprinciple, the printing material is pushed by pins coupled to theclamping means for the screen. The material is pushed along thestationary plate of the printing table during the printing process. Thishas i the disadvantage thatlonly completely rigid material can beprinted on such a machine. Moreover, the material itself, which issqueezed onto the plate by the pressure of thesqueegee, must beinsensitive to the friction thereby created, 'as'it would otherwise bescratched undemeath.

With the machine according to the invention, on the other hand, theprinting material which may be hard or soft; lies on the advancingbaseplate during the printingprocess and so cannot be damaged byfriction. This advantageconsiderably' widens the range of material whichcan'be printed on the machine.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows various stages I to VII inthe operation of a screen printing machine according to the invention;

FIG. 2 shows the machine of FIG. I in plan view;

FIG. 3 shows the machines of FIG. 1 in side view;

FIG. 4 is a longitudinal section on line IV-IV of FIG. 5;

FIG. 5 is a plan view of the embodiment of FIG. 4;

FIG. 6 is a longitudinal section on line VI-VI of FIG. 7;

FIG. 7 is a plan view of the embodiment of FIG. 6;

FIG. 8 is a cross section through another embodiment;

FIG. 9 is a fragmentary section on line IX-IX of FIG. 8;

FIG. 10 shows yet another embodiment in sections and in one position;

FIG. 11 shows the embodiment of FIG. 10 in another position;

FIG. 12 is a side elevational view of an actual embodiment of anapparatus according to the invention;

FIG. 13 is an end view of the apparatus in FIG. 12;

FIG. 14 is a top plan view of FIG. 12;

FIG. 15 is a side elevational detail view of the blocking means used inthe embodiment of FIGS. 12l4;

FIG. 16 is a top view of FIG. 15;

FIG. 17 is an end elevation of FIG. 15 looking toward the right;

FIG. 18 is an end elevational view illustrating further details of theblocking means;

FIG. 19 is a side view of FIG. 18; and

FIG. 20 is a top plan view of FIG. 19.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1-3 a clamping means 1for a printing screen 7 is rigidly connected to a baseplate 2 andmounted for longitudinal movement in a table. The baseplate 2 is movedto and fro by a drive of any type, in uniformly long strokes H. Inposition I the combined baseplate 2 is in its starting position, withprinting material 8 thereon which is supplied by known feed meansdiagrammatically illustrated, this material being brought into positionII on being moved forward the length of the stroke H. The length of thisstroke is such that the material 8 passes through under a stationarybridge 3 fixed to the frame, after which the bridge is lowered byconventional means and acts as a barrier for the printing material whenthe baseplate 2 carries out the return stroke H. In this way thematerial 8 is transported forward through other positions. Between eachof the positions IVII there is a forward or return stroke in thedirection of the arrow.

The bridge 3 is twice the length of the stroke and has three barriers 9,9'. In position II the barrier 9 holds back the material 8. In positionV the material 8 is below the printing screen 7, which is fixed in theclamping means I. When the baseplate 2 moves forward, the material 8 isprinted by a stationary squeegee 4 which is controlled in known manner,e.g. by a cam and is lowered for printing at the desired time. Anyslipping between the baseplate 2 and the material 8 is avoided byproviding a suction in a chamber 10 and perforation 10' in the baseplate2, the material being secured in the various stations by suctionproduced by the diagrammatically illustrated suction means (FIG. l/II).

After the printing process, position VII is reached by the sameprinciple of advance and the material 8 is removed. In order thatmaterial 8 of different thicknesses can be processed, the clamping means1 for the screen, the bridge 3 and the squeegee 4 are mounted forvertical adjustment in known manner.

As shown in FIGS. 2 and 3, the ends of the longitudinal sides of thebridge 3 are provided with angled portions 11 which terminate and arepositioned in the table. The baseplate 2 is let into the table andslides therein on rails I2.

In FIGS. 4 and 5, instead of having the stationary bridge 3, lengthwiseslots 13 are provided in the reciprocating base 2', these slotscooperate with pins 5 which can be lowered and which are fixed to theframe. The pins 5 are controlled by an arrangement (not shown) and arelowered beneath the surface of the baseplate 2 on the forward movementof the latter. On the backward movement of the plate 2 the pins 5project beyond its surface and prevent the printing material 8 fromrunning back with the plate. Pairs of slots 13 and pins 5 are offsetfrom one another for each length of stroke H and are staggered (see FIG.5),

In FIGS. 6 and 7 lateral blocking arms 6 are provided instead of thepins 5 which can be lowered; the arms 6 can always be drawn far enoughapart from the middle to center the printing material 8 lying on thebaseplate 2 and let pass on the forward movement; on the backwardmovement of the baseplate 2 they are moved far enough together towardthe middle of the baseplate in at least substantial parallelism with theplane of the upper surface thereof to prevent the material 8 fromreturning. The barrier 9, pins 5 and arms 6 hold back the 'material 8when the baseplate 2 carries out the return stroke, and have theadvantage of enabling many different types of material to pass throughand be printed. Thus, instead of the sheets illustrated they will alsolet through e.g. plastic parts, plastic folders, ash trays, saw blades,tiles, rectangular bottles and parts with no parallel surfaces.

In FIGS. 8 and 9 the material 8 is to be printed in prismatic crosssection and a guide 14 for it is mounted on the baseplate 2. The bridge3 is provided with a barrier 9 which, when lowered, cooperates with thematerial 8 in the manner described earlier.

In FIGS. 10 and 11 the printing station is equipped so that the material8 is received by a pickup implement. Thin lids are shown as an exampleof the material 8; at the printing station these are picked up by theplunger P, which, when it is raised for the printing presses, acts as asupport and which, when the material 8 is advanced, is lowered into theplane of the baseplate 2.

FIGS. 1220 show actual embodiments of the invention, by contrast to thediagrammatic illustrations in FIGS. 1-l1.

The apparatus illustrated in FIGS. 12-15, wherein the elements have thesame reference numerals as their counterparts in the preceding FIGS.insofar as possible, shows a screen 7 whose distance or height withrespect to the base 2 may be adjusted; this is evident from FIG. 13.Clamping means 1 serves to hold screen 7 in the associated frame 26 andin the manner known to those skilled in the art.

It will be appreciated that the possibility of adjusting the distance ofscreen 7 from the base 2 makes it feasible to utilize the apparatus witha great variety of different printing materials-i.e., materials to beprinted-of diverse thickness and configuration.

The clamping means comprises two portions, one of which is movablewhereas the other is rigid with the base 2 and therefore movable withthe latter without play. The squeegee is stationary and the printingframe 26 moves with reference to it. Blocking members 9 cooperate withbridge 3, and pins 5 with slots 13 and plate 2.

The clamping device 1 comprises two elements rigid with base 2 andcarrying the frame 26 for the The 7 in the illustrated manner. Theframe, and thereby the screen, are tiltably mounted with the tiltingaxis located at one end of frame 26. At the opposite end there areprovided on the frame two arms with adjusting spindles 30; these arearranged to move onto inclines 31 which are stationary, so that theframe 26 is lifted when this occurs. Four grippers 27 secure the screen7 to the frame 26. Four bolts, and other, nonillustrated securing meanssecure the clamping device 1 to the base 2.

The height adjustment to accommodate thicknesses in the printingmaterial, as mentioned before, is effected by means of screws 29 whichpermit adjustment of elements 1, 7, 26 and 30 as a unit with referenceto the base 2.

Squeegees 4 and 33 are tiltable in the sense indicated by the associatedarrow; rough adjustments in the height of squeegee 4 are effected byvirtue of the presence of recess 32' of the members 17, while fineadjustments are carried out via a spindle 32. Two screws 34 permitadjustment of the position of squeegee 33.

As shown, one end of a lever 16 is connected to a rod 38 while the otherend is associated with a drive cylinder 22. Similarly, one end of alever 35 is connected to a rod 39 while its other end is connected withdrive cylinder 23. A further cylinder 21 serves to effect moving of thebridge 9 with the aid of portions 11 which are guided in slots 13 ofbaseplate 2. Cylinder 20 provides motive power for the latter. Valvesfor the various cylinders are not separately illustrated; they arelocated in housing 24 and connected via a conduit 25 which communicateswith a compressor. Hose 18 movably connects chamber with a stationaryvacuum pump.

Both of the squeegees 4 and 33 are tiltably mounted on arms 41 havingaxis 40 and connected by a spring 42. Squeegee 33 is adjustable bytilting about rod 39 through arms and cooperating longitudinal slots 34.It is connected by spring 42 with the left-hand outer arm 41 (FIG. 13).Spring 42 is a torsion spring connected to rod 39 and to a projection ofthe arms 41 in question. A similar connection exists between theleft-hand inner arm 41 and the rod 39 about which element 33 turns. Theright-hand arm 41 serves as an abutment. Rods 12 act as guides forbaseplate 2 and are connected to the baseplate 2 by loops 43, and withthe frame 26 by the arms 44. Cylinders 23 are stationary. The springsurge elements 4 and 33 against the associated left-hand arms 41 and theelements are fitted from this operating position, and lifted off by thelevers l6 and 25, respectively so that the elements then both extend inthe same direction. The somewhat difi'erent showing in FIG. 13 has beenchosen to preserve clarity of illustration. Slots 34 extend along twoother arms which are transversely secured to element 33. Abutments onrod 39 are as sociated with screws 34.

In FIGS. I5l7 in which like reference numerals again identify likeelements, a cylinder 36 is seen to be connected with spring-loaded pins5 via lever 45, pairs of members 46 and rods 47. Cylinder 36 isstationary. This embodiment thus shows in detail what has been describedwith reference to the diagrammatic illustration in FIGS. 4 and 5.

FIGS. 17-20 show the use of two stationary cylinders 37 which areassociated with the arms 6 and the members 48. The latter are mounted onrods 49 shiftable in transverse slots 13', with the rods beingstationarily secured to the machine frame. In this embodiment themembers 48 replace the pins 5 and correspond to the lateral blockingarms 6 of FIGS. 6 and 7, with their movement between blocking andunblocking positions being enabled and guided by the presence of theslots 13'.

As already mentioned, the drawings only show examples of the invention;the invention is not restricted to these, and other embodiments andapplications are possible. It is, however, essential for the baseplateto be rigidly connected to the clamping means for the screen and toparticipate in the entire forward and backward strokes, whateverparticular embodiment may be chosen.

While the invention has been illustrated and described as embodied in ascreen printing machine, it is not intended to be limited to the detailsshown, since various modifications and structural changes may be madewithout departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

I claim:

I. In a screen printing machine, in combination, baseplate means havingan upper surface and being reciprocable longitudinally in predetermineddirections in alternate working and return strokes of predeterminedlength, so that material to be printed and which may be located on saidsurface moves with said baseplate means; screen means mounted above saidbaseplate means for movement toward and away from the upper surface ofthe same; blocking means associated with said baseplate means andoperative during the respective return strokes of the same for blockingmaterial on said surface from moving with said baseplate means, wherebysuch material advances stepwise over said upper surface and beneath saidscreen means in one of said predetermined directions; clamping meanscooperating with said screen means for clamping the same against saidbaseplate means when material to be printed is located beneath saidscreen means; and squeegee means mounted for engagement with said screenmeans in response to operation of said clamping means to thereby effectprinting of material located beneath said screen means.

2. In a machine as defined in claim 1, said blocking means comprisingbarrier means mounted for displacement in direction normal to said uppersurface.

3. In a machine as defined in claim 1, said blocking means comprisingbarrier means mounted for displacement in at least substantialparallelism with the plane of said upper surface.

4. In a machine as defined in claim 1, said blocking means comprisingthree cooperating barrier elements arranged spaced from one another inlongitudinal direction of said baseplate means and being movable inunison with one another relative to said upper surface between ablocking position which they assume during the respective returnstrokes, and an unblocking position which they assume during therespective working strokes.

5. In a machine as defined in claim 1, wherein said upper surface isprovided with a plurality of slots extending longitudinally thereof; andwherein said blocking means comprises a plurality of projections eachregistering from below said baseplate means with one of said slots andbeing movable between a working position in which it is partly locatedin the associated slat and partly extends upwardly of said uppersurface, and a retracted position in which it is entirely withdrawn intothe associated slot.

6. In a machine as defined in claim I; and support means associated withsaid baseplate means and operative for supporting material to be printedon said baseplate means in a predetermined position.

7. In a machine as defined in claim 1, said baseplate means havingopposite lateral sides, and said blocking means comprising blockingmembers located at said opposite lateral sides of said baseplate meansand being movable towards one another transversely of said predetermineddirections.

8. In a machine as defined in claim 1; and further comprising guidemeans for material to be printed and operative so as to guide suchmaterial during the advancement thereof.

9. In a machine as defined in claim 8, said guide means being mounted onsaid baseplate means.

10. In a machine as defined in claim 8, wherein said guide meanscomprises a guide element of substantially prismatic cross-sectionalconfiguration.

1. In a screen printing machine, in combination, baseplate means havingan upper surface and being reciprocable longitudinally in predetermineddirections in alternate working and return strokes of predeterminedlength, so that material to be printed and which may be located on saidsurface moves with said baseplate means; screen means mounted above saidbaseplate means for movement toward and away from the upper surface ofthe same; blocking means associated with said baseplate means andoperative during the respective return strokes of the same for blockingmaterial on said surface from moving with said baseplate means, wherebysuch material advances stepwise over said upper surface and beneath saidscreen means in one of said predetermined directions; clamping meanscooperating with said screen means for clamping the same against saidbaseplate means when material to be printed is located beneath saidscreen means; and squeegee means mounted for engagement with said screenmeans in response to operation of said clamping means to thereby effectprinting of material located beneath said screen means.
 2. In a machineas defined in claim 1, said blocking means comprising barrier meansmounted for displacement in direction normal to said upper surface. 3.In a machine as defined in claim 1, said blocking means comprisingbarrier means mounted for displacement in at least substantialparallelism with the plane of said upper surface.
 4. In a machine asdefined in claim 1, said blocking means comprising three cooperatingbarrier elements arranged spaced from one another in longitudinaldirection of said baseplate means and being movable in unison with oneanother relative to said upper surface between a blocking position whichthey assume during the respective return strokes, and an unblockingposition which they assume during the respective working strokes.
 5. Ina machine as defined in claim 1, wherein said upper surface is providedwith a plurality of slots extending longitudinally thereof; and whereinsaid blocking means comprises a plurality of projections eachregistering from below said baseplate means with one of said slots andbeing movable between a working position in which it is partly locatedin the associated slot and partly extends upwardly of said uppersurface, and a retracted position in which it is entirely withdrawn intothe associated slot.
 6. In a machine as defined in claim 1; and supportmeans associated with said baseplate means and operative for supportingmaterial to be printed on said baseplate means in a predeterminedposition.
 7. In a machine as defined in claim 1, said baseplate meanshaving opposite lateral sides, and said blocking means comprisingblocking members located at said opposite lateral sides of saidbaseplate means and being movable towards one another transversely ofsaid predetermined directions.
 8. In a machine as defined in claim 1;and further comprising guide means for material to be printed andoperative so as to guide such material during the advancement thereof.9. In a machine as defined in claim 8, said guide means being mounted onsaid baseplate means.
 10. In a machine as defined in claim 8, whereinsaid guide means comprises a guide element of substantially prismaticcross-sectional configuration.